THINGS TO KNOW ABOUT SOLID STATE BATTERIES
vijay tharad
Director Operations at Corporate Professional Academy for Technical Training & Career Development
WHAT’S SOLID-STATE BATTERIES?
Solid state batteries are regarded as an important development for the future. Their particular advantage is that solid-state batteries do not contain any liquids that could leak or catch fire. For this reason, they are significantly safer, more reliable and more durable than current lithium-ion batteries with liquid electrolyte. At the same time, solid-state batteries have the potential to store more energy in the same space with less weight.
ADVANTAGES
Solid-state batteries offer the potential for:
1. What are solid-state batteries?
As the name implies, a solid-state battery is a battery in which all the components that make up the battery are solid. Secondary batteries (batteries that can be recharged and used repeatedly) like lithium-ion batteries are basically composed of two electrodes (a cathode and an anode) made of metal and an electrolyte that fills the space between them. Conventional secondary batteries use a liquid as the electrolyte, but solid-state batteries use a solid as the electrolyte.
It is expected that the solid electrolyte will enable larger-capacity and higher-output batteries than lithium-ion batteries. Moreover, making the electrolyte solid has advantages in terms of safety over lithium-ion batteries. They are therefore attracting attention for installation in electric vehicles and other products.
In this way, it is said that solid-state batteries would have various benefits if they could be put into practical use. Currently, different companies are competing in product development and the realization of mass production for large-volume supply.
2. How do solid-state batteries work?
Solid-state batteries have almost the same mechanism as lithium-ion batteries for extracting electricity from the batteries. Metal is used as the material for the electrodes, and electrical flow is generated by ions moving through the electrolyte between the cathode and anode. The big difference is that the electrolyte is solid. Also, when the electrolyte is a liquid, there is a separator that separates the cathode from the anode, preventing the liquid on the cathode side from mixing suddenly with the liquid on the anode side. But in the case of a solid electrolyte, the separator is unnecessary.
The key to research into solid-state batteries is the discovery and/or development of solid-state materials. In the past, no solid-state material had been discovered that could allow ions to move around inside and create a sufficient flow of electricity to the electrodes. But the discovery of such materials has given momentum to the development of solid-state batteries. By changing from a liquid to solid electrolyte, the ions will move well in batteries, making it possible to create batteries with larger capacity and higher output than lithium-ion batteries.
3. What are the types of solid-state batteries?
Solid-state batteries are broadly classified into “bulk” and “thin-film” types depending on the manufacturing method, with the amount of energy they can store differing.
Type Characteristics Anticipated uses
Bulk Can store a lot of energy Electric vehicle batteries, etc.
Thin-film Can store only a small amount of energy
, but lasts a long time IoT devices, etc.
Characteristics of bulk solid-state batteries
Powders (substances consisting of powder, granular material, etc.) are used as the materials of the electrodes and electrolyte. It is possible to make large-capacity batteries that can store a lot of energy. It is anticipated that they will mainly be used for large things such as electric vehicles.
Characteristics of thin-film solid-state batteries
These are batteries manufactured by stacking a thin-film electrolyte on the electrodes in a vacuum state. The amount of energy stored is small and they cannot produce a large capacity. However, there are advantages such as a long cycle life and ease of manufacturing. Because they are small, they are suitable for use in small devices such as sensors.
4. How are they different from lithium-ion batteries? A description of the benefits of solid-state batteries
Solid-state batteries, which are expected to be the next generation of secondary batteries, are considered to have the following benefits.
Can withstand low to high temperatures
Since the electrolytes in lithium-ion batteries are made of flammable organic solvents (liquids that dissolve substances that do not dissolve in water), there is concern about their use in high-temperature environments. On the other hand, since the electrolytes in solid-state batteries are not made of flammable materials, they can be used at higher temperatures.
Further, in the case of liquids, the movement of ions slows at low temperatures, causing battery performance to drop, and the voltage may decrease. In the case of solids, the internal resistance does not increase so much and battery performance does not drop much because the solid does not freeze like a liquid even at low temperatures.
Fast charging is possible
The benefit of being resistant to high heat is also advantageous for fast charging. The faster batteries charge, the more they heat up. Because of this, it is believed that it will be possible to charge high-temperature-resistant solid-state batteries even faster than current lithium-ion batteries.
Long lifespan
The lifespan of a battery depends on the properties of the electrolyte. Since lithium-ion batteries do not use a battery reaction like other secondary batteries, the electrode deteriorates little and lasts a long time, but when used for a long time, electrolyte deterioration can be seen. In that respect, since the electrolytes in solid-state batteries deteriorate less than liquids, it will be possible to extend battery lifespan even further.
High degree of freedom in shape
Liquid electrolytes have structural restrictions to prevent liquid leakage. But in the case of solid-state batteries, there is no such limitation. So, they can be used in various shapes because it is easy to make them smaller and thinner, and because they can be used while overlapped or bending.
5. What are the applications of solid-state batteries?
One of the expected applications for solid-state batteries is electric vehicles. Currently, electric vehicles use lithium-ion batteries. But if they used solid-state batteries, the risk of ignition due to accidents is expected to decrease since they do not contain flammable organic solvents. In addition, whereas today’s electric vehicles take longer to charge than refueling with gasoline, with solid-state batteries it will be possible to charge them more quickly.
In addition, one of the reasons why the practical application of solid-state batteries is being actively pursued is that they can compensate for lithium-ion batteries’ weak point of being vulnerable to high temperatures. Since they could be soldered directly to an electronic substrate by taking advantage of their heat-resistant characteristic, it is also anticipated that their uses will include electronic device backup power supplies and IoT sensors. If used in PCs or smartphones, they should enable powerful operation for a longer time.
Furthermore, since solid-state batteries can achieve a larger capacity and higher output than lithium-ion batteries, they can be expected to be used in airplanes and ships. And since they are resistant to temperature changes across the spectrum from high to low temperature, it can be expected that their applications will expand to include devices used in outer space.
6. How safe are solid-state batteries?
Solid-state batteries are hard to short-circuit because the electrodes are separated by a solid, and they can be used at higher temperatures because they use highly heat-resistant electrolytes. However, since all batteries are “canned energy,” solid-state batteries are not risk-free. Care must be taken when handling them, as the electrodes may short-circuit for some reason.
7. What are the challenges to the practical application of solid-state batteries?
Research and development into higher-performance solid electrolyte materials is underway with the aim of putting solid-state batteries into practical application in the early 2020s. The following challenges must also be solved to achieve this.
Challenge of a solid electrolyte
In order for batteries to perform well, the electrodes and electrolyte must always be in close contact. Liquid electrolytes always change shape, so they can maintain close contact even if the electrode changes a little. With solid-on-solid, on the other hand, there is the challenge that it is difficult to always maintain close contact.
Challenge of electrode materials
In order for solid-state batteries to significantly increase energy density over existing lithium-ion batteries, it is necessary to develop electrodes that can store more power at the same weight and size.
Challenge of the manufacturing process
Since the electrolyte will be changed from liquid to solid, a manufacturing process different from lithium-ion batteries is needed. For example, solid-state batteries can be based on oxides, sulfides, nitrides, etc., depending on the material. The solid electrolytes used in solid-state batteries based on sulfides, which is one of the mainstream types, are so sensitive to moisture that they degenerate even when exposed to moisture in the air. Therefore, the production of solid-state batteries, which require strict moisture control, will need dedicated facilities such as dry rooms.
As mentioned above, various companies are currently making efforts to commercialize solid-state batteries, which are expected to further enhance the performance of lithium-ion batteries. On the other hand, lithium-ion batteries are actively used in a wide range of fields. Part 5 explores how lithium-ion batteries will play a role in realizing a sustainable society.
The difference between lithium-ion batteries and solid-state batteries
Lithium-ion batteries are the current battery of choice for commercial applications. It is a proven technology that is economically competitive and thus easily scalable for mass-use. The major drawback of these batteries are its modest energy density (around 250 Wh/kg) and safety concerns regarding thermal runaway, causing the battery to catch fire. Thermal runaways are rare in everyday use technologies but should be avoided if possible. Solid-state lithium-metal batteries could provide answers to these problems. With an improved safety and higher energy density of around 400 Wh/kg, they have the ability to not only improve current technology (lifetime, charge time, etc.), but provide new opportunities like electric flight. To understand where these advantages come from, we need to understand the difference in working mechanisms.
Lithium-ion batteries have three key components: a negatively charged anode, a positively charged cathode and a separator in between. The anode and cathode are porous, allowing for liquid electrolyte to move positively charged lithium between the two electrodes. This movement of charge causes free electrons in the anode to move to the cathode, creating a current. This current provides the electricity that is used to operate a cellphone or an EV. An empty battery is charged by reversing this process.
?
Discharging lithium-ion battery. (Figure: Econopolis Strategy)
In solid state batteries the liquid electrolyte is replaced by a solid electrolyte, this makes it an All-solid-state battery (ASSB). As the liquid electrolyte poses the most danger in terms of flammability, the solid-state battery is much safer. Solid electrolytes also are compatible with better performing anode materials such as silicon or lithium metal. Lithium metal has about 10 times the specific capacity of the graphite that is typically used in lithium-ion batteries, increasing the energy density. The three most researched solid-state batteries use electrolyte materials such as sulfide, oxide and polymers. These all have different metrics in terms of safety, production difficulty and performance.
What are the differences between lithium-ion and solid-state batteries?
Lithium-ion batteries consist of electrical contacts alongside four other main components:
When you turn on a?car that uses a?lithium-ion battery, it closes and connects the circuit the battery is part of. This causes the positively charged lithium ions to move through the liquid electrolyte, and the separator, from anode to the cathode. This causes chemical reactions that generate electrons, which move in the opposite direction in the external circuit and generate the electrical current powering the car. When charging, the ions and current move in reverse.
In contrast, solid-state batteries contain a?solid lithium metal anode and a?solid ceramic electrolyte – which also acts as the separator. Here, the separator becomes part of the solid medium through which the lithium ions move. When charging, the lithium ions form a?solid layer of lithium on the anode. This has a?smaller volume than the anode in a?lithium-ion battery – meaning more energy can be generated by a?smaller battery.?
Characteristics of different electrolyte materials in solid-state batteries
SAFETY PRODUCTION DIFFICULTY PERFORMANCE
SULPHIDE LOW MEDIUM HIGH
OXIDE HIGH HIGH MEDIUM
POLYMER MEDIUM LOW LOW
?CHALLENGES AND GAPS FOR SOLID STATE BATTERIES
CHALLENGES AND GAPS FOR SOLID STATE BATTERIES
All types of batteries lose a significant amount of their theoretical potential due to practical limitations, but a solid-state lithium-metal battery still outperforms lithium-ion batteries in terms of safety and energy density. One of the major drawbacks, however, are the degradation mechanisms in the solid-state type batteries. The solid electrolyte does not perfectly block lithium dendrites from forming when charging. This causes a short circuit if it reaches the cathode. Discharging the battery on the other hand, can lead to interfacial delamination, causing spots on the anode to lose contact with the electrolyte. Furthermore, combined with phenomena like lithium creep and dead lithium, these batteries need replacement after extensive charge and recharge sequences.
Forming of dendrites over lifetime of solid-state batteries
(Figure: Econopolis Strategy)
?
Other important challenges are cost and usability. The handling and manufacturing of solid-state batteries are more complex, which is reflected in the cost. This also prohibits the mass production and integration of these types of batteries in everyday use. Other restrictions are caused due to useability. Solid-state batteries have had poor performances while operating at low temperatures. Stabilizing them to be useful at room temperatures is not always a given. Furthermore, pressure considerations make them more fragile. All these issues can be fixed but will come with a cost in terms of lowering the energy density. Nevertheless, researchers are hopeful solid-state batteries will find their applications in pacemakers, wearables, electric vehicles and space equipment.
It is vital to address issues common to battery technologies, with fire safety, energy density, durability and recyclability chief among them. The challenges, they note, are many:
Unresolved fundamental issues remain in the quest to fully understand the behavior of all-solid batteries, especially in the area of electrochemical interfaces.
Parameters that require robust understanding from a product development standpoint are material cost, cell lifetime and shelf life, cell energy density on a volumetric and gravimetric basis, operable capabilities for given temperature conditions, and safety.
The advantage of energy density remains to be realized in solid state electrolytes (SSEs) since most studies to date utilize thick SSEs or cathodes with low active loading compared to liquid counterparts.
The desire to use Solid State Electrolytes in conjunction with Li metal anodes requires understanding and managing the morphology of Li metal plating, which can impact volumetric energy density.
Although operation at both higher and lower temperature compared to conventional technologies is a significant potential advantage of SSE systems, reports of solid state cells achieving parity with traditional systems at room temperature or any other temperature do not currently exist.
The decreased flammability of SSE systems is another potential advantage but requires ongoing validation and study.
The manufacturability and material component costs of SSEs have not been well characterized, and thus the value of these features will need to be weighed accordingly with any added cost.
The operating lifetime of SSEs capturing intrinsic materials parameters such as voltage stability as well as catastrophic failure modes such as shorting have been briefly investigated, but in the absence of high energy density electrode formulations and application based testing protocols that are comparable to commercial liquid electrolyte cells.
Materials Science Gaps
Progress on solid-state batteries surges following the discovery of promising solid electrolytes. However, every known solid electrolyte has one or more drawbacks that must be overcome to enable the development of viable solid-state batteries for EVs. Work should continue to discover new electrolytes, with the expectation that other performance and processing criteria are simultaneously satisfied. Furthermore, a clear understanding of the challenges to integrating components into batteries will inform the search for new materials.
Science Gaps for the Li Metal Anode
The following questions need to be answered to fill the science gaps that exist in the development of an optimized Li metal anode:
Science Gaps for the Solid Electrolyte in Contact with Li Metal
The community has learned much about failure at the Li/solid electrolyte interface in recent years. More specifically, we see that
(1) effective passivation of the interface reduces Li consumption,
(2) a high-modulus solid electrolyte formed with a dense, smooth interface suffers fewer issues related to Li roughening,
(3) a higher fracture toughness inhibits cracks that may form shorts,
(4) higher electronic resistivity mitigates Li+ reduction within the solid electrolyte separator. Given this background, several important questions were identified:
Science Gaps for Active Cathode Materials and Solid-State Composite Cathodes
For the highest energy density, the cathode must be the most voluminous component of the battery. For example, suppose the cathode serves as the mechanical support and battery substrate. In that case, the current collectors, separator, and Li anode can all be applied as thin coatings with limited volume, weight, and cost, as shown in Figure 3. In traditional slurry cast cathodes, organic binders may suffice to form freestanding cathodes, or polymer electrolytes can be added to fill voids and facilitate Li+ transport. The composite cathode may also be bonded, fused, or sintered to improve interfacial contact. These steps complicate the processing but ensure the formation of mechanically robust solid–solid interfaces. The key is to fabricate a cathode that will (i) withstand stresses during cycling and (ii) provide facile electronic and ionic transport at low stack pressure (<1 MPa).
In summary, solid-state batteries hold great promise for high-energy batteries for EVs and other applications. While the potential is great, success is contingent on solving critical challenges in materials science, processing science, and fabrication of practical full cells.
Challenges
Li metal solid-state batteries have the potential to provide advantages in
However, success is not assured, and solid-state battery development faces several challenges, including
In Nature Nanotechnology, UCSD researchers outline four considerations that should stay at the forefront of solid-state battery development, namely:
Solid-state batteries make a?good alternative to conventional lithium-ion batteries for several reasons:?Solid-state batteries have multiple advantages as compared to traditional batteries. They offer high energy density, better safety, and a longer lifespan.
Solid-state batteries Disadvantages
It has been proven that it is very difficult to make solid-state batteries work. There are multiple challenges in making effective solid-state batteries.
What are the disadvantages and challenges of Solid state batteries?
Although the internal constituents of batteries vary based on construction, lithium is a key factor in most. Globally, lithium prices have tripled in the past year alone, and that's despite global lithium production tripling in just the past five years. There is, quite simply, a global shortage of the stuff.
领英推荐
The problem is that solid-state batteries could actually use even more lithium than today's lithium-ion packs. Remember those higher-density anodes mentioned above? They'll likely be made of pure lithium metal. "Now, lithium metal can increase the specific energy of your battery by up to three times but it comes as pure lithium, which means the lithium intensity is also increased," McNulty said, noting this will exacerbate the lithium shortage.
"It's going to be between five and 10 times the amount of lithium for the same battery," said Dr. Jordan Lindsay, research and innovation manager at Minviro, a U.K. consulting firm that quantifies the environmental impacts of raw material production. "So, if you can nail recycling for that, cool. But if not, we're already projecting difficulties with supply chains for normal lithium-ion, so I have no idea how we resource solid-state."
Recycling Issues
According to Lindsay, as of now there are no effective ways to recycle solid-state packs.
"One of the issues with solid-state is that we're going to have to get better at recycling lithium. Currently, with lithium-ion batteries, you can recycle nickel, cobalt, manganese pretty well—aluminum and copper from the cell components pretty well," Lindsay said. "But, graphite and lithium are the issue. They're the sticking point from wholesale, closed-loop battery recycling. They're still working out the efficiencies of it."
Recycling could help address the supply chain issues, while easing environmental concerns, but Lindsay worries it may not come soon enough to address the situation: "There is this huge criticality on materials, and I don't think it's been addressed as seriously as it could be."
He continued: "I think there is this sort of messy scramble to try and get ahead and the industrial side of recycling for batteries because it's really important in terms of LCA [life cycle assessment], not necessarily an environmental impact, because the recycling processes are quite energy intensive by themselves, but in terms of reducing strain on supply chains. It's essential. We will not be able to make all these batteries without recycling."
Dendrites
Quick refresher: In solid-state batteries, the anode and cathode are separated by a solid electrolyte. That means smaller, denser batteries and higher-density, pure lithium for one of the electrodes.
So far, so good, right? Well, researchers have been spotting a problem, one that also plagues the lithium-ion batteries that power today's EVs, especially when they are repeatedly charged at high-power, fast-charge stations. As these batteries age, the shape of the lithium electrode has been changing, growing in weird, organic ways. The lithium is forming what are called dendrites, branching structures of metal that literally grow into the solid electrolyte.
Eventually, those dendrites grow long enough to reach through to the other side of the electrolyte, shorting out the battery pack. Again, that's bad news. Recent MIT research has determined the dendrites form due to internal stresses within the battery construction. By applying other physical stresses, those researchers found they can inhibit the dendrite growth. However, as these results are fresh out of the lab, it could be years before a solution can be applied to mass-manufacture.
Cost
Perhaps the biggest drawback of all is cost. Solid-state batteries not only require higher densities of rare metals, but their construction technique is wholly different from that of today's lithium-ion cells. That means new factories, new procedures, and new benefits of scale manufacturing that are still being invented.
There is, however, potential for these batteries to be even cheaper—eventually. "The first commercialization of a solid-state battery will not be cost-competitive with [today's] lithium-ion batteries; it will come at a cost premium," McNulty said. "But those benefits in safety and drive range and that kind of thing would likely make up for that. It's over time, over the first five to 10 years of commercialization, that it will begin to become cost-competitive as the technology improves."
All of that sounds great, and it's no wonder there are dozens of startups working on bringing solid-state batteries to market, many with big funding from major OEMs and optimistic projections of product launches by 2025. That may be optimistic, though. Let's look at some of the roadblocks.
It has been proven that it is very difficult to make solid-state batteries work. There are multiple challenges in making effective solid-state batteries.
So, When? We will have SOLID STATE BATTERIES FROM MANUFACTURERS
Some manufacturers are reportedly producing solid-state batteries in cars within the next few years, but it's clear this will be on an extremely limited scale to start.
"So if we're talking about mass production, I would say 2030 is an optimistic suggestion for when the first solid-state batteries will begin to be purchasable on scale by consumers," McNulty said. "And those first vehicles really will be testbed systems that will be really expensive. They'll be high-performance, but I think the idea of those vehicles would be to get used to the technology, and I don't think there'll be wanting to build significant quantities of those until they're sort of mastered what the technology is like in the natural EV application."
McNulty says 2032 to 2035 is a more realistic estimate for when we might see solid-state-battery EVs in mass production. That gives battery developers about a decade to figure out the recycling and supply chain issues. But Minviro's Lindsay is optimistic that we might also be more frugal with our car battery construction by then: "It sounds sort of silly and simple, but just halving the battery size would reduce the strain loads," he said. "I think the conversation has to be about halving battery size, making batteries that function how people need."
Getting over your range anxiety, then, might be the final key to making solid-state batteries work.
Do electric vehicles use solid-state batteries?
Yes, some electric vehicles use solid-state batteries. They are the most promising technology for future generations of batteries in the field of electric vehicles. Solid-state batteries offer high thermal stability and a longer lifespan. Hence they are safer and more efficient than traditional electric vehicle batteries.
According to Transport and Environment (T&E) commission, solid-state batteries can store more energy using fewer materials and are able to reduce the carbon footprint of an EV battery by 39% by using sustainably sourced technology and proper materials.
Lithium-ion batteries power much of our technology; from the mobile phones in our pockets to large battery-powered trucks. But solid-state batteries may be a?more powerful, compact, safe, and sustainable option, especially for electric vehicles.
Gel Electrolytes: Bridging the Gap
A subset of solid-state batteries incorporates gel electrolytes. These gels provide a compromise between the liquid electrolytes in traditional batteries and the solid electrolytes in fully solid-state batteries. Gel electrolytes enhance safety and mitigate the risk of thermal runaway while retaining some of the benefits of solid-state designs.
Anatomy of Solid-State Batteries vs. Lithium-ion Batteries
Solid-state batteries boast solid electrodes and electrolytes, eliminating the need for a liquid medium. In contrast, lithium-ion batteries rely on liquid electrolytes where ions move between anode and cathode during charge and discharge cycles.
Safety First: The Thermal Runaway Dilemma
One of the chief advantages of solid-state batteries is improved safety. The solid electrolyte mitigates the risk of thermal runaway, a phenomenon often associated with lithium-ion batteries, reducing the likelihood of fire or explosion.
Liquid Electrolytes: A Double-Edged Sword
Lithium-ion batteries, while successful, have inherent drawbacks. Liquid electrolytes pose safety risks, such as short circuits and the potential for thermal runaway, which could compromise the safety of electric vehicles and electronic devices.
Energy Density: Solid-State’s Edge
Solid-state batteries offer higher energy density compared to traditional lithium-ion counterparts. This means more energy can be stored in the same volume, opening avenues for compact and lightweight battery designs, crucial for electric vehicles.
The Prowess of Rechargeable Batteries
Both solid-state and lithium-ion batteries are rechargeable, but solid-state batteries, with their solid electrolytes, exhibit longer cycle life. This means they can endure more charge and discharge cycles before experiencing a decline in performance, a key factor for sustainable energy solutions.
The Speed Game: Charging Faster with Solid-State Batteries
Solid-state batteries have the upper hand in charging speed. The absence of a liquid electrolyte allows ions to move more swiftly between the anode and cathode, enabling faster charging times compared to traditional lithium-ion batteries.
The Price Tag: Cost-Effective Solutions
While the production of solid-state batteries is a complex and evolving process, advancements may lead to cost-effective manufacturing. Currently, traditional lithium-ion batteries hold the edge in terms of production cost, but ongoing research and development may close this gap.
Electric Vehicles in Focus: Driving the Future
The battle between solid-state and lithium-ion batteries intensifies in the context of electric vehicles. Solid-state batteries offer the allure of enhanced safety, higher energy density, and faster charging, while lithium-ion batteries maintain their stronghold due to cost-effectiveness and established manufacturing processes.
What are All-Solid-State Batteries
Introduction
All-solid-state batteries (ASSBs) have emerged as a promising solution to address the limitations of traditional lithium-ion batteries (LIBs). These batteries offer the potential to revolutionize industries ranging from electric vehicles to renewable energy systems. By replacing the liquid electrolyte found in LIBs with solid materials, ASSBs aim to enhance safety, increase energy density, and extend the overall lifespan of energy storage systems. In this article, we’ll introduce all-solid-state batteries, similarities and differences to LIBs, ongoing research challenges, and instrumentation requirements.
The main difference between ASSBs and LIBs is the state of their electrolytes. Traditional LIBs have a liquid or gel electrolyte, whereas ASSBs employ solid electrolytes. Figure 1 illustrates the structural distinctions between ASSBs and LIBs. The positive and negative electrodes act as either anode or cathode depending on whether the device is charging or discharging. A range of solid electrolytes are currently being explored and include ceramics, polymers, resins and glass composites. [1] There are some safety concerns posed by LIBs due to their flammable nature that may be improved by ASSBs by reducing the risk of leakage, thermal runaway, and dendrite formation.
In addition to improving safety, all-solid-state batteries also offer higher energy densities compared to traditional LIBs. This means that ASSBs can store more energy in the same amount of space, making them especially attractive for applications that require compact energy storage solutions like electric vehicles and portable electronics. ?Having unique transport, thermal and mechanical characteristics, ASSBs can also potentially address the major issues encountered with LIBs and overcome fast charging limitations. [2]
Figure 1: A schematic comparison between the structure of a traditional lithium-ion battery (left) and an all-solid-state battery (right), during discharge.
Research Endeavors and Obstacles
The transition from liquid to solid electrolytes introduces its own set of challenges. Some of these challenges include:
Reduced conductivity of solid electrolytes at room temperature
Solid-state batteries exhibit lower ionic conductivity compared to traditional liquid electrolyte batteries due to the inherent nature of solid electrolytes. Ions are not as free to move around in solids, or even polymers, as they are in liquids because ions must move through lattices and grain boundaries. Conductivities of Li+ solid electrolytes tend to be 2-4 orders of magnitude lower than liquid electrolytes. [3] This decreased mobility is related to a higher activation energy barrier and is temperature dependent.
WHAT ARE THE PROSPECT FOR SOLID STATE BATTERIES TO BECOME REALITY FOR ELECTRIC VEHICLES
Production Challenges: Scaling Solid-State Battery Manufacturing
lndustry experts predict that solid state batteries could start making their way into the automotive market by the mid to late 2020s. However, initial adoption may be limited to high-end electric vehicles before becoming more mainstream.
The Solid-State Revolution: An Overview
Solid-state batteries represent a paradigm shift in energy storage. Unlike traditional lithium-ion batteries that use liquid electrolytes, solid-state batteries employ solid electrolytes, promising enhanced safety, higher energy density, and longer cycle life.
The production of solid-state batteries poses challenges, from the intricacies of creating solid electrolytes to scaling up manufacturing processes. Overcoming these challenges is crucial for solid-state batteries to become a mainstream solution.
At the moment, China has the potential to dominate the next stage of the industry because of its leadership in both battery technology and manufacturing: it produced more than 75 per cent of batteries globally last year, according to the International Energy Agency.
CATL is by far the world’s biggest battery maker, boasting a market share of 37 per cent. The Ningde-based company is the most profitable battery maker and has a formidable cost advantage, in part because of its scale and investment in research and development. Solid-state might be the only way to leapfrog Beijing in the battery race.
Toyota is far from the only company investing in the technology. Nissan and Honda have their own programmes. South Korea’s three leading battery producers — LG Energy Solution, Samsung SDI and SK On — have all declared their intention to develop such cells by the late 2020s.
US start-ups QuantumScape and Solid Power, partners of Volkswagen and BMW, respectively, have similar commercialisation target dates for their own technologies.
Akitoshi Hayashi, professor at Osaka Metropolitan University, says it will be “extremely challenging” to mass-produce solid-state batteries to the same quality as current lithium-ion batteries, but if achieved, the technology will be “globally unbeatable”. “Solid-state batteries will be key to the revival of Japanese carmakers, who are behind in EV strategy and for Japan, which has lost world market share in lithium-ion batteries,” he adds. China also controls the processing of battery raw materials. Solid-state batteries could reduce certain vulnerabilities such as the current reliance on graphite, which Beijing placed export restrictions on last week. But they would do little to ease forecasted lithium shortages since they would consume even more than current batteries. Industry leaders in China and Korea are less sanguine about solid-state batteries achieving their promise. According to a person close to CATL, the Chinese group’s researchers have been working for the past decade to crack solid-state batteries. They have yet to find a cost-effective system for mass production — and, internally at CATL, there is scepticism that Toyota has achieved this. Korean industry leaders concur. “Developing a product and commercialising it are two different matters,” says one executive. “Toyota has been talking about mass production of solid-state batteries for [more than] 10 years, but they keep delaying the timing.” Manufacturing obstacles Even if technology and scale-up challenges can be overcome, it is a huge unknown whether solid-state batteries can bring production costs down in time to accelerate the global rollout of EVs. Economies of scale will help reduce costs. But the performance and cost of current lithium-ion batteries are also improving constantly, as other technologies such as silicon anodes make advances. Solid-state batteries’ extreme sensitivity to moisture and oxygen could keep manufacturing costs high, while their complexity could require expensive redesigns of EVs. If the costs do not come down enough, then solid-state batteries could end up being limited to luxury cars or trucking. Kim Dong-myung, head of the advanced automotive battery division of Korea’s LGES, says that producing them is “too costly” and there will be “very limited applications”. Even if everything goes as planned, solid-state batteries can only take about 10 per cent of the overall market for EVs by 2035, estimates Lee Kyung Sub, head of the battery materials business at Korean conglomerate Posco. Toyota’s chief executive Koji Sato himself has been hesitant to call solid-state batteries “a game-changer” for winning the global EV race. Sato has indicated that solid-state batteries will initially be rolled out in small volumes in high-end models, while lithium-ion batteries will continue to be used for more affordable cars. “Solid-state battery technology will be an extremely important factor in terms of building our overall strength in the various battery products that we have,” Sato said last week. “But batteries alone will not determine the value of our vehicle.” Many industry executives agree that solid-state’s constituent technologies will gradually be integrated into today’s batteries. CATL appears to be planning to do exactly that, unveiling in April a new “condensed”, or “semi-solid-state”, battery with double the energy density of current models. “A fully solid-state battery is an ideal of where we want to go,” says Glen Merfeld, chief technology officer at Albemarle, the world’s largest lithium producer. “Today’s lithium-ion batteries will end up evolving to look like that.” For all the technical obstacles that remain, some observers believe the potential impact could be profound. A battery with substantially improved performance could open up a redesign of many aspects of global mobility, ranging from robotaxis to regional aviation and new kinds of drones. “Solid-state has to fulfil a mission. The job of new batteries is never to replace old batteries. It’s to unlock things we couldn’t do previously,” says Shirley Meng, battery professor at the University of Chicago. “By leveraging on the new driving range and charging time, the Japanese car companies are reimagining the future of transportation.”
Navigating the Future of Energy Storage (Advantages and Disadvantages)
Advantage: Solid-State Batteries Are Safer Than Lithium-Ion Batteries. EV Fires Could Be A Thing Of The Past. Safety Advantages Of Solid-State Batteries
Using ceramic electrolytes in sold-state batteries helps prevent dendrites from growing the same way they do in a liquid electrolyte battery. This ensures the battery won’t short out internally. Automakers can also incorporate solid-state batteries into a vehicle’s structure, which makes them much safe than lithium-ion alternatives.
Advantage: Solid-State Batteries Are More Energy Dense.Electric Vehicle Weight Changed. Energy density describes how much actual electricity a battery can put out for a given weight or volume. Current EV batteries are extremely heavy, weighing much more than internal combustion engines in most cases. A change to new battery technology should come with a lower weight, but that also means these batteries must be more energy dense than current models.
Increase Energy Density Allows:
Some reports suggest these new solid-state batteries could be three times more energy-dense than current lithium-ion cells. This means automakers could have the option between weight savings or adding driving range to electric cars. A lithium-ion battery that weighs 1,000 pounds could offer the same energy as a solid-state battery that weighs only 333 pounds.
Advantage: Rapid Charging To Full Will Be Possible. Forget The 80-percent Charge Problem
Current electric cars are capable of charging to 80-percent of their full capacity at DC fast-charging locations. This limit is set to protect the batteries, which could be damaged from the extreme flow of electrons. Unfortunately, this reduces the actual driving range while on a road trip. EVs that list a driving range of 300 miles are reduced to 240 miles per charge when using these charging stations.
Charging Advantages Of Solid-State Batteries
The solid electrolyte of these new batteries allows charging to full capacity at public fast-charging stations. The reduced charging times using these batteries in electric cars could finally challenge the short time it takes to refill a gas tank with fuel. Solid-state batteries could reduce charging times to 10 or 15 mines versus the current time it takes to recharge lithium-ion batteries.
Advantage: Solid-State Batteries Are Highly Stable. Fewer Chain Reactions Due To Temperature Issues.Driving electric cars under normal conditions is perfectly safe. If they weren’t, there wouldn’t be the increased push to have more EVs on the road. When the battery gets too hot or is damaged, a chain reaction could create a fire that engulfs the entire vehicle. The increased heat can be caused by improper charging, and damage can occur in an accident.
What Makes Solid-State Batteries More Stable?
Without liquid electrolytes, charging and collision damage can be minimized, greatly reducing the risk of an EV catching fire. There is still some risk; if a solid-state battery becomes damaged, it could catch fire, but the smaller size and build allows automakers to protect them better than current lithium-ion batteries.
Advantage: Greatly Reduced Battery Construction Time. Forget The Liquid Building lithium-ion batteries takes a long time. Once the cell is built, the filling and conditioning phase begins. This phase requires the liquid electrolyte to be applied and gently charged, and discharged, which allows the electrodes to form the protective coating. This is a lengthy process that could slow the supply chain of batteries into electric vehicles.
Reduced Battery Construction Time Means:
Many automakers function on just-in-time supply logistics, which means a specified number of parts is available at the right time to avoid storing mass quantities of parts. The construction time difference between solid-state batteries and lithium-ion batteries is nearly three weeks. Imagine the reduced assembly time with batteries made three weeks faster than before.
Disadvantage: Solid-State Batteries Require Rare Earth Metals Material Shortages Could Become Problematic
Lithium is a Rare Earth metal, and prices of lithium have tripled recently even though global production of lithium has also tripled. You might think replacing lithium-ion batteries with solid-state models would change the chemistry, and it does, but not the way you want. Solid-state batteries could use more lithium than current EV batteries, which could lead to a shortage of materials.
How Can We Avoid Materials Shortages?
How much more lithium will new EV batteries use? Some experts estimate the among required could be five to ten times the amount of lithium required to build these new batteries. This will put pressure on recycling efforts and learning how to reuse all battery materials.
Disadvantage: Automakers Need Special Battery Factories Construction Isn’t The Same Many automakers invested billions of dollars into lithium-ion battery factories located in proximity to EV assembly plants. Switching to solid-state batteries would reset these costs and require new factories to build these new batteries. This added investment will likely cause early solid-state equipped EVs to be more expensive than those with lithium-ion batteries.
What Solid-State Battery Benefits Outweigh the Costs?
The first five to ten years of solid-state battery usage might cause increases in EV prices, but once these batteries are the industry norm, prices could reduce and become more affordable for drivers. Unfortunately, current electric cars are more expensive than gas powered vehicles; another increase could push some EVs out of contention for many consumers.
Disadvantage: Currently No Effective Way To Recycle EV Batteries.New Tech Requires New Discoveries
Electric cars use complicated technology and batteries. The newness of this technology means working toward methods of recycling or reusing EV batteries.. Some automakers have discovered ways to utilize the remaining energy in batteries once they’re no longer useful in cars, while others are working toward recycling the materials in current lithium-ion battery packs.
Disadvantage: Dendrites Grow In Lithium-Based Batteries. Higher Density Could Shorten Battery Life. If solid-state batteries become the norm for electric cars, some warnings will be required. It's been discovered that as batteries age and are repeatedly charged at high-power, fast-charging stations, the shape of the lithium electric begins to change. They grow in strange organic ways with branching structures called dendrites.
Difference In Construction:
The challenge with dendrites is they can grow long enough to reach through to the other side of the electrolyte, which would short out the battery pack. This could reduce the battery life of solid-state batteries. Automakers may need to warn against the consistent use of fast-charging stations.
How Are Automakers Recycling/Reusing EV Batteries?
Currently, many of the materials in lithium-ion batteries can be recycled. These metals include nickel, cobalt, manganese, aluminum, and copper. The challenge is recycling graphite and lithium.
Solid-state batteries and lithium-ion batteries each bring unique strengths and weaknesses to the table. As technology advances, the choice between them becomes a pivotal decision for industries, especially in the burgeoning electric vehicle sector. Whether it’s the quest for higher energy density, faster charging, or improved safety, the future of energy storage hinges on understanding and harnessing the strengths of both solid-state and lithium-ion batteries.
FREQUENTLY ASKED QUESTIONS
What is the range of a solid-state battery?
Similarly, Toyota announced in October that it plans to incorporate solid-state batteries in an unnamed number of production vehicles by 2027. The automaker said it is targeting a 1,000-km (600-mile) range with 80 percent DC fast-charge in 10 minutes or less.
What are the limitations of solid-state batteries?
Low temperature operations may be challenging. Solid-state batteries historically have had poor performance. Solid-state batteries with ceramic electrolytes require high pressure to maintain contact with the electrodes. Solid-state batteries with ceramic separators may break from mechanical stress.
What is the theoretical capacity of a solid-state battery?
In addition, by using metallic anode material (lithium) instead of the usual graphite, solid-state batteries achieve higher energy densities—theoretically up to 11 kWh/Kg. In practice, 1 kWh/Kg seems realizable, which is still four times higher than the current lithium‐ion batteries.
How much more power can a solid-state battery hold?
Solid-state batteries have a higher energy density per unit area due to their compact size. The energy density of a solid-state battery can be up to ten times greater than that of a lithium-ion battery of the same size.
Can solid-state batteries be charged to 100%?
A solid state battery replaces the gel with a solid electrolyte that won't overheat, so needs no bulky cooling system. By Nissan's reckoning we're looking at half the cost per kWh versus today's gel batteries, and twice the energy density. They would charge three times as fast, and sustain that to 100 per cent.
Can solid-state batteries freeze?
Solid-state batteries' electrolytes are solids instead of liquids, so they circumvent the risk of freezing or dramatically dropping in performance, like batteries affected by recent winter weather in the United States.
Do solid-state batteries lose capacity?
A lithium-ion battery will begin to degrade and lose power capacity after 1,000 cycles. A solid-state battery will maintain 90% of its capacity after 5,000 cycles. This allows solid-state batteries to be lighter, have more energy density, offer more range, and recharge faster.”
Why aren't we using solid-state batteries?
Some key reasons include: 1. Complex Manufacturing Processes: Solid-state batteries often require more intricate manufacturing processes compared to traditional lithium-ion batteries. Achieving consistency and scalability in production can be challenging, leading to higher costs.
Can solid-state batteries be cylindrical?
There has recently been an increase in the need for larger capacity all-solid-state batteries that can also be applied to main power applications including sensing applications such as infrastructure monitoring. The new cylindrical all-solid-state battery under development is responding to such requirement.
What is the difference between a solid-state battery and a normal battery?
The main difference between a solid state battery and the lithium-ion batteries currently used in electric cars is a component known as the electrolyte. In a lithium-ion battery, the electrolyte is a gooey liquid. In a solid state battery, the electrolyte is, well, a solid.